At present, various materials are used as adhesives or adhesive agents also called bonding agents in various fields. For example, for use in individuals like mammals, in particular, in humans, various adhesives are described in the field of fixation of dental restorations or orthodontic applications on implants, abutments or teeth, as well as in other implant applications.
In dentistry cements are in principle divided in three groups, (1) provisional cements, (2) conventional cements and (3) adhesive luting materials (adhesive cements).
(1) Provisional cements are used for a short period of time (up to 6 months) to fix provisional restorations on teeth or implants or implant-abutments. The cementation can be destroyed/loosen using nippers or special devices using an impulse which is transmitted to the provisional restoration. Normally the restoration can be removed without breaking the restoration. On the other hand these cements are not stabile over time and caries can appear on the abutment tooth or the restoration might get loose unpredictably.
(2) Conventional cements compose a hard layer between definitive restoration and the teeth, implants or implant-abutments. This layer is stable within the oral cavity over time and holds the restoration in place over years. There is no or only low chemical bonding between the cement and the materials of the restoration, the teeth, the implants or the implant-abutments. Normally the restoration can be removed from the teeth, implants or abutments only by destroying the restoration.
(3) The adhesive cementation has the same characteristics as the conventional cement, however there is an additional chemical adhesion to the different materials like tooth structures, implant and implant-abutment materials (for example titan, gold alloy, all-ceramic materials). Therefore this type of cementation is even stronger than the conventional cementation and it can be used even to fix less frictional type of elements (for example veneers, inlays), definitive splints for teeth or brackets.
In particular, for fixation of implants in dental applications, an adhesive luting is applied. Typically, dental cements are used for adhesion. Dental cements are permanent non-removable or provisional dental cements which are either resin cements or acid-based cements. Acid-based cements are typically in form of a powder of a basic metal oxide or silicate and an acidic liquid for hardening. Alternatively, resin-based cements are used in the field of dentistry and tooth restoration. Furthermore, non-aqueous acid-based cements like zinc oxide eugenol and non-eugenol zinc oxide are known. These non-aqueous acid-based cements contain metal oxide fillers embedded in a metal salt matrix. Dental cements are used for a variety of dental and orthodontic applications, including use as luting agents, pulp protecting agents or cavity-lining material. In addition, they are used to form an insulating layer under metal-ceramic or all-ceramic restorations and protect the pulp from injury.
Dental implants are alloplastic materials which are provided in the area of the jaw bone. Said implants are used for fastening dental prosthesis. Typically, said implants are in two parts form composed of the implant body and the abutment. The abutment is fixed with the implant body by fastening means, e.g. by screwing. Restoration by crowns or bridges as permanent dental prosthesis is achieved by adhesion materials, like dental cement.
Until today, the dental cement used for fixation of prosthesis are designed for permanent fixation of the dental prosthesis. However, it is desired to allow removal of the dental prosthesis in case of technical and biological complications, e.g. clinical complications, or in case of ceramic chipping.
However, removal of the provisional or permanent restorations involves typically destruction or damage of the implant, abutment, abutment screw or restoration. Thus, re-use of the permanent restorations, e.g. the crowns and bridges, is hardly possible. Further, in case of the provisional fixation of a provisional restoration with adhesive materials designed for provisionals, the risk of an undesired loosening of the provisional may occur, thus, resulting in aspiration or swallowing of the provisional. On the other hand, permanent restorations may be removed only by destruction of the restoration. The destruction requires the complete restoration of the implant including new preparation of the restoration material.
Orthodontics brackets are adhesively cemented on the enamel of the teeth. When later the brackets have to be removed again, the brackets must be removed with special nippers. However there is adhesive cement remaining on the tooth structure, which has to be removed with diamond or hard metal burs in a second step. This procedure is time consuming and there is always the risk to remove not only the adhesive material, but also part of the tooth structure,
Hence, there is a need for a new adhesive material allowing permanent fixation of seconds elements, like restorations on first elements present in the body of the patient, like implants or teeth, in particular for dental and orthodontic applications, allowing a removal of the means, like restorations or dental applications without destruction of the first and second elements fixed on each other like restorations, teeth or implants.